Qrop® KS increased income for coastal potato farmers in Peru

Making farmers aware of the benefits of potassium nitrate helps them to successfully achieve higher yields and better quality tubers. Top quality tubers are heavier and have less skin damage, so they command a higher price, which translates into higher income.

In the city of Barranca - a coastal valley 200 km north of Lima - farmers apply potassium as potassium sulfate and potassium chloride. The choice of these sources limits farmers to applying potassium only in the first cover crop, when the crop's requirement for this nutrient is much lower than in the later stages.

Image 1. Team at work: From left to right: Alci Soto, Oscar Rodriguez, Reymand Durand, Rodrigo Real, Juan Vasquez, Yamil Adum, Jhonathan Salinas.

The SQM Vitas Peru team demonstrated excellent results using potassium nitrate in ^Qrop® KS as the main potassium source for coastal potatoes in Peru, increasing yields of premium potatoes by replacing potassium sulfate and reducing the use of potassium chloride.

Reymand Durand is a leading potato farmer in the area. The SQM Vitas Peru team proposed an improved potato nutrition program, providing a balanced fertilization, based on the use of _KNO3 as the main potassium source. ^Qrop® KS is a chloride-free potassium source that fits into an optimal nutrition program, allowing a balanced _NO3:NH4 ratio_{and a} potassium supply at the time of peak demand in the potato crop.

More than 8,000 years ago, the potato was domesticated in the Peruvian Andes, and today it is an important food crop worldwide. Of a total of 4,000 varieties of potatoes known worldwide, more than 3,000 are still grown in Peruvian soils.

With more than 300 thousand hectares, potato is one of the most abundant crops in Peru. It is also an important cash crop, generating 4% of agricultural GDP (Gross Domestic Product).

Although almost 90% of the production of this crop is concentrated in the Peruvian Andes, there are several production centers on the coast, where the high technological level and good management of the crop make the "coastal potato" an attractive product for local markets, supermarkets, and restaurants in the region.

Table 1. Fertilizer sources, application time, rates and nutrients applied with each treatment.

Three nutritional programs were compared on areas of 0.5-1.5 ha (Table 1): The farmer's traditional program, with only two applications during crop development, a low _N-NO3:_N-NH4 ratio and no use of potassium nitrate. Plus two programs including the use of ^Qrop® KS, with the total fertilizer split into three application times, a more than 1.3:1 ratio of _N-NO3:_N-NH4, no use of potassium sulfate, and reduced application of potassium chloride. The two ^Qrop® KS programs varied in the relative amounts of potassium nitrate application at the three application times, in the level of KCl reduction, and the total amount of fertilizer applied. Yield was evaluated during the farmer's harvest on a sample of more than 0.3 ha from each treated field.

Image 2. Potato crop at the time of the second fertilization.

Image 3. Harvest day.

Table 2. Tuber yields following SQM's farmer practice and nutritional program.

Outstanding Results The results of Mr. Reymand Durand's trial were excellent. The yield of tubers fertilized with ^Qrop® KS exceeded the yield of potatoes using the farmers' practice.

The use of ^Qrop® KS increased total tuber yield by 21% following the second program. The total quantity of first-class quality tubers increased by 8%. The additional cost of the SQM program was well compensated: it resulted in a net income increase of 7%.

Table 3. Farmer income and profits following farmer practice and SQM nutrition programs.

What's next? Following this trial, the Business Development team of SQM VITAS Peru, together with the commercial area, is developing an action plan to efficiently communicate the good results of this work to other farmers, distributors and institutions and replicate it in other areas.